\mycommand{first argument}[second argument]

\begin{myenv}
her
e
is
a
lin
e
tha
t
con
tai
ns
sim
ple
tex
t
her
e
is
a
lin
e
tha
t
con
tai
ns
sim
ple
tex
t
her
e
is
a
lin
e
tha
t
con
tai
ns
sim
ple
tex
t
her
e
is
a
lin
e
tha
t
con
tai
ns
sim
ple
tex
t
her
e
is
a
lin
e
tha
t
con
tai
ns
sim
ple
tex
t
\end{myenv}
